What is an "impresario"? Well, you know one when you meet one, and Michael White, the subject of Gracie Otto's enormously entertaining documentary The Last Impresario, certainly is one. With theatrical credits as original producer of The Rocky Horror Show, O Calcutta and Sleuth, and film credits such as Monty Python and the Holy Grail, The Rocky Horror Picture Show and My Dinner With Andre, he really is, as the poster claims, "the most famous person you have never heard of."